Summon not working?

[MartinT]

For some reason when I try to cast a summon the unit just remains on Defend and doesn't cast. I have rank 6 fire on the manticore god and I'm trying to summon fire drake. I also have summon apsaras and that one works fine.

The other fire summon, bind scorpion, does the same thing. I have the gems/requirements and it behaves like it should work it's just that the caster remains in defend mode instead of casting when I select those summons.